Voltage converters are widely used in industrial, automotive or consumer electronics applications for converting a first voltage into a second voltage, wherein the first voltage and the second voltage are different in at least one of a voltage level and a signal waveform. Switched-mode converters (switched-mode power supplies) include at least one switching element that generates a pulse-width modulated (PWM) voltage from the first voltage, and the PWM voltage is received by a rectifier circuit that generates the second voltage from the first voltage. The voltage level of the second voltage can be controlled by controlling a duty cycle of the PWM voltage in this type of voltage converter.
There are switched-mode converters in which the rectifier circuit includes a transformer that provides for a potential barrier between an input where the first voltage is applied thereto, and the output where the second voltage is available. In this type of converter, the switching element is usually coupled to the primary winding of the transformer, that is the switching element is arranged in a primary side section of the rectifier circuit, while the second voltage is available in a secondary side section of the rectifier circuit. In order to be able to control the output voltage by suitably switching the switching element, the voltage level of the output voltage needs to be communicated from the secondary side section to the primary side sections.
There is therefore a need to provide a method and a circuit for efficiently communicating a voltage level of a voltage converter output voltage from a secondary side to a primary side.